Author: Richard Pijl
Date: 02:30:33 11/26/02
Go up one level in this thread
On November 26, 2002 at 04:43:16, David Rasmussen wrote: >[D]r4rk1/1p1n1pp1/1bq1bn1p/p1pp4/2P2B2/1NNP2P1/PPQ2PBP/R4RK1 w - - 0 19 > >Chezzz encountered this position in a game. This position, and some immediately >before and after it, made Chezzz go nuts in quiescence search: > >time nodes depth score pv >00:00:00.14 52kn 02/02/16 --------------------------------------------------- >00:00:00.14 53kn 03/03/08 +0.055 19. Nb5 a4 20. Nd2 >00:00:00.17 66kn 03/03/12 +0.100 19. Rae1 Rae8 20. Nb5 >00:00:00.25 88kn 03/04/14 --------------------------------------------------- >00:00:01.37 631kn 04/04/16 +0.205 19. Rae1 a4 20. cxd5 Nxd5 > 21. Nxd5 Bxd5 >00:00:01.78 804kn 04/04/16 --------------------------------------------------- >00:00:02.08 953kn 05/06/16 +0.205 19. Rae1 a4 20. cxd5 Nxd5 > 21. Nxd5 Bxd5 >00:00:02.59 1191kn 05/06/16 +0.277 19. Rfe1 a4 20. Nd2 Rfe8 > 21. cxd5 Nxd5 22. Bxd5 Bxd5 > 23. Rxe8+ Rxe8 24. Qxa4 Qxa4 > 25. Nxa4 >00:00:04.14 2020kn 05/06/18 +0.410 19. Qd2 Rfe8 20. Rae1 Red8 > 21. Qe3 >00:00:04.20 2040kn 05/06/18 --------------------------------------------------- >00:00:06.00 3083kn 06/08/18 +0.370 19. Qd2 Rfe8 20. Rae1 Rec8 > 21. Qe3 Bc7 >00:00:07.39 3728kn 06/08/19 --------------------------------------------------- >00:00:11.06 5684kn 07/10/21 +0.483 19. Qd2 Rfe8 20. Rae1 Kf8 > 21. cxd5 Nxd5 22. Nxd5 Bxd5 > 23. Rxe8+ Kxe8 >00:00:12.47 6313kn 07/10/21 --------------------------------------------------- >00:00:28.12 14Mn 08/11/22 6/48 19. Rae1 > > Time used: 00:00:30.00 > nps: 497701 nodes: 14936023 Q-nodes: 14513023 (97%) > move order: 88% > hash probes: 112554 hash hits: 26981 (23%) hash usage: 2% > pawn hash probes: 14816435 pawn hash hits: 14807848 (99%) > EGTB probes: 0 EGTB hits: 0 (0%) > >97% Q-nodes!! >In the other positions near this, it was the same. 97-98%. I don't have the most >brilliant Q-search, but it's not totally naive either. I don't do checks, and I >use SEE to order moves and to throw out moves that won't bring the score up >close to alpha. In usual middlegames, I see percentages of 10%-40%. > >So how do your engines do in this positions? >What can be done to lower this number? > >/David Baron has no problem with this position, although the number of qnodes is a bit above average (60%, normally around 35-40%). Baron does do checks in qsearch, as well as SEE for move ordering and pruning In addition, Baron also stores qsearch results in the hashtable (without a hashmove to prevent bad move ordering) and uses them for pruning as well. ply time nodes score pv 5( 6)& 0 38233 31 f1e1 a5a4 c4d5 f6d5 b3d2 5( 6). 0 68691 31 f1e1 a5a4 c4d5 f6d5 b3d2 6( 8)& 1 90456 27 f1e1 a5a4 b3d2 f8d8 a1c1 d8e8 6(10). 2 150838 27 f1e1 a5a4 b3d2 f8d8 a1c1 d8e8 7(11)& 2 225183 28 f1e1 a5a4 b3d2 a4a3 c4d5 f6d5 b2b3 7(11). 4 425419 28 f1e1 a5a4 b3d2 a4a3 c4d5 f6d5 b2b3 8(12)& 5 511255 24 f1e1 a5a4 b3d2 a4a3 c4d5 f6d5 c3d5 e6d5 8(12)& 16 1383298 33 a1e1 a5a4 c4d5 f6d5 b3d2 8(12)& 30 2500162 38 a2a4 a8e8 c2d2 e8a8 a1e1 8(12). 30 2509812 38 a2a4 a8e8 c2d2 e8a8 a1e1 9(14)& 54 4594582 55 a2a4 f8d8 f1e1 d7f8 c4d5 f6d5 g2d5 e6d5 e1e7 9(14). 60 5207482 55 a2a4 f8d8 f1e1 d7f8 c4d5 f6d5 g2d5 e6d5 10(15)& 147 12366860 40 a2a4 f8d8 f1e1 d7f8 f4e3 f8g6 e1e2 d8d6 a1e1 10(15). 192 16267180 40 a2a4 f8d8 f1e1 d7f8 f4e3 f8g6 e1e2 d8d6 a1e1 Computer's move: a2a4 Nodes: 16267180 Qnodes: 9730431 Moves left: 0 Time: 192 seconds Clock: 33361 seconds TB probes: 0 TB hits: 0
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